Color tube processing apparatus



Sept. 26, 1967 R- J. PEKQSH 3,343,198

COLOR TUBE PROCESSING APPARATUS Filed Nov. 12, .1965 2 tsSheet 1 IN VEN'TQR. 9 Raymond J Pekosh A'rforn Sept. 26, 1967 R. J. PEKOSH COLOR TUBE PROCESSING APPARATUS 2 Sheets-Sheet 2 Filed Nov. 12, 1965 m m m M W V m A d v n e United States Patent Ofifice 3,343,198 Patented Sept. 26, 1967 3,343,198 COLOR TUBE PROCESSING APPARATUS Raymond J. Pekosh, Chicago, Ill., assignor to The Rauland Corporation, Chicago, 111., a corporation of IlllllOlS Filed Nov. 12, 1965, Ser. No. 507,441 6 Claims. (Cl. 15306) The present invention pertains to apparatus for processing a color cathode-ray tube of the type which features a color-selection mask positioned in close spaced relation to the image screen area. The so-called shadow-mask tube is one form of color image reproducer that may be processed by the apparatus of this invention. Other forms of tubes that may, likewise, benefit from utilization of the invention are those which make use of a switching grid, as distinguished from an apertured shadow mask, for the purpose of color selection.

Color tubes of the type under consideration have envelopes of two principal parts, a cap section which provides the image screen surface and a funnel or conical section terminating in a reduced diameter neck which houses the electron guns. It is customary to employ a two-part envelope to facilitate screening, that is to say, establishing the desired pattern or phosphor elements on the screen area of the cap section. It has also become established practice to havesupports in the cap section to which the mask may be aflixed in order to position the mask properly relative to the screen area.

In screening such a tube, one color phosphor is usually applied at a time which frequently entails applying to the screen area a layer of a composition including the desired phosphor and a photosensitive resist. Exposure of that layer and subsequent developing in a technique that is now well known to the art establishes a desired pattern of the phosphor being processed.

The exposure of the coating applied to the image area is through the mask which requires that the mask be inserted into the cap section after the coating has been applied but prior to exposure. At this point in the processing cycle, the entire coating on the screen area is soluble in water and if Water splashes on the layer as an incident to inserting the mask, there is a very serious possibility of destroying the screen. This danger is very real in that it is usually necessary to wash the coating material off the flange of the cap in What is known as a trim process. If the mounting supports take the form of studs extending inwardly from the flange of the cap, they are wet as a result of the trim operation, therefore, inserting the mask may easily result in splashing water from the studs to the image surface.

It is an object of the present invention to provide processing apparatus for color tubes in which this source of screen reject is minimized if not totally eliminated.

It is a specific object of the invention to provide color tube processing apparatus in which insertion of the color selection mask may be accomplished during screening without any serious risk of damages to the screen in process.

It is another particular object of the invention to provide an improvement in color tube processing apparatus which removes water from the mask supports of the color tube after the trim process.

Apparatus embodying the invention is utilized for processing a color cathode-ray tube having a cap section comprised of an image screen area surrounded by a continuous flange having supports for mounting a color selection mask in predetermined spaced relation to the screen area. The apparatus comprises a workholder for supporting the cap section for rotation. There is an exhaust system including a fixture having an exhaust channel extending therethrough and terminating in a nozzle which has a recess dimensioned to at least partially enclose one of the mask supports of the cap section. This fixture is movable from a rest position in which the nozzle is out of the path of movement of the mask supports to an exhaust position in which at least one of the mask supports is presented to the recess of the nozzle. Finally, there are means for moving the exhaust fixture between its rest and exhaust positions in timed relation to the rotation of the cap section by the workholder.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which:

FIGURE 1 represents one station of'a color screening apparatus which features the subject invention;

FIGURE 2 is a view taken as indicated by section line 2-2 in FIGURE 1;

FIGURE 3 is a detail of the nozzle of an exhaust fixture included in the apparatus of FIGURE 1;

FIGURE 4 is a sectional view taken along line 4-4 of FIGURE 3.

Referring now more particularly to FIGURE 1, the color tube processing apparatus there represented is arranged for screening the cap section 10 of a round color cathoderay tube of the shadow-mask variety. It makes little difference whether the tube be round or rectangular; the apparatus to be described may be utilized in processing either subject, of course, to the necessary specific modifications that the configuration of the tube imposes on the apparatus, such as, the arrangement .of the workholder. In either event, the cap section has an image screen area 10a surrounded by a continuous flange 10b in which there are provided means for mounting a color selection mask in a predetermined spaced relation to the image screen area. Where the tube is of the shadow-mask variety, the contour of the mask corresponds very closely to that of the cap section and it carries along side flanges mounting springs to engage the mounting provisions of the cap section and removably support the mask in position. Obviously, it makes little diflerence whether the mask support in the cap section is a recess for accepting a mounting stud carried by the mounting springs of the mask or, as illustrated, mounting studs 10c projecting radially inwardly of flange 10b for accepting an aperture in the mounting springs of the mask. The commercial structure in use today usually employs three or four mask supports 10c spaced about flange 10b of the cap section and the aperture mask has a corresponding number of mounting springs with mounting holes dimensioned and shaped to easily snap over mask supports in positioning the mask in place. This mask structure is well known in the art and has not been shown on the drawing.

A complete screening machine for processing the cap section of a color tube is described and claimed in an application Ser. No. 391,864, filed Aug. 25, 1964, in the name of Joseph P. Fiore and assigned to the assignee of the present invention. That apparatus performs what is known as slurry screening in which a slurry coating of a photosensitive resist and a desired phosphor is applied to the cap section of the tube at one of the many work stations of the screening machine. After the slurry coating has been applied, one or more gentle jets of water are directed to the flange of the cap section as that section is rotated in order to trim or wash the slurry that may have been deposited on the flange of the cap section. After the trimming has been accomplished, the cap section is advanced to the next station of the machine where v) the coating is dried preparatory to exposure. The present invention may be readily understood from a consideration of only so much of the drying station of such a machine as is concerned with drying or removing water from mask supports 100 which will have been thoroughly wetted during the trim process.

The cap section of the tube is carried to the process station to be described by means of a screening cart comprising a Workholder 11 having a hub 11a from which extend radial arms 111;. There are generally three such arms, one of which is provided with a pivoted clamp 11c which may close against a cap section inserted within the clamp defined by arms 11]] to lock it firmly in order that it may be rotated as the Workholder is driven.

Workholder 11 may be rotated by a driving system enclosed within a housing 12. The details of the drive are of no particular concern. It may include a motor carried by the screening cart that is stopped along from one processing station of the screening apparatus to the next. For present purposes, it is sufficient to consider that the workholder may be driven from a gear system 12a to rotate the cap section at a selected speed.

As described in the Fiore application, it is desirable to be able to tilt the cap section of the tube in order to have it assume a desired angle at the various processing stages of the screening machine. This may be accomplished, for example, by means of a tilt rail 12b which extends along the run of the machine and is engaged by followers 13 that extend from motor casing 12 of the screening cart. If the casing is supported on its cart to be displaced about a horizontal axis, followers 13 in conjunction with the specific contouring of tilt rail 12b may readily control the disposition or angle of cap section 10 relative to a horizontal or other reference plane.

The support plate of the screening cart is designated 14 and it has structural components 14a, 14b by means of which drive casing 12 may be mounted to the cart for rotation about a horizontal axis. A, frame comprising standards 140, shown in fragmentary view in FIGURE 1, is carried by the screening cart merely as a place to store the color selection mask that has been assigned to the cap being processed. Further details of the screening cart and a suitable driving system are disclosed in the Fiore application which is incorporated herein by reference. No further detail is required for an understanding of the invention that is claimed here.

According to the subject invention, an exhaust system is added to the station under consideration which otherwise is used primarily to accomplish drying of the slurry layer that had been previously applied and trimmed. The exhaust system has an exhaustpump and includes a fixture 21 having an exhaust channel 22 extending from the pump completely through the fixture to a terminating nozzle 23.

As shown most particularly in FIGURES 3 and 4, the nozzle has a channel section 23:: which forms a continuation of exhaust channel 22 when the nozzle is in position, locked to fixture 21 by set screw 23b. The nozzle has a shoulder portion 23c which properly locates the nozzle in respect of fixture 21 and there is an extension 24 of the nozzle which is formed to provide a guide portion and further to provide a recess dimensioned to at least partially enclose one of the mask supports 100 of the cap section 10. As shown most clearly in FIGURE 3, the nozzle extension 24 has a passageway 24a which extends across the exhaust channel 23a. The extension 24 is essentially U-shaped in cross section as illustrated in FIG- URE 4 but the legs of the U are of different lengths. The longer leg 24b serves as a guide for engaging flange 10b of the cap section under process to position the nozzle relative to the mask supporting studs 10a of that cap section. The leg 24b is in essentially line contact. with the flange 10b when the nozzle is in its operative position. With this type of engagement, the guide 24b may trace and follow panels that are either of round or rectangular configuration so that the nozzle is flexible in use.

Exhaust fixture 21 is movable from a rest position in which nozzle 23 is out of the path of movement of mask supports 10c to an exhaust position in which at least one of the mask supports is presented to the recessed passage of the nozzle. The illustrations all show fixture 21 in its exhaust position; the alternate position is one wherein the fixture is totally removed from the tube cap under process. The mechanism for accomplishing the movement in timed relation to the rotation cap 10 by Workholder 11 includes a motor drive 30 which is coupled through a suitable gearing 31 to a heart-shaped cam 32. A pair of limit switches 33 and 33a control motor 30 in response to a switch operator 33b which rotates with the drive shaft to the end that the cam 32 oscillates over the arc ofapproximately 180 whenever motor 30 is energized. This drive arrangement is mounted on a standard 34 which also can ries linkage mechanically coupled to exhaust fixture 21. This linkage includes a shaft 35 which is rotatably supported by stand 34 and terminates at one end in a lever 36 which carries a follower 37 for cam 32 and, at its free end, attaches to a spring 38 which biases shaft 35 counterclockwise. The other end of shaft 35 terminates in a fork or U-shaped member 40 which rotatably supports a pin 41 carried by a generally J-shaped lever 42. At one end.

of lever 42, there is a cam follower 43 for engaging a stationary cam 44 and this lever is also attached to a bias spring 45 which urges lever 42 in a clockwise direction about its pivot 41. The opposite end of lever 42 carries a pair of clamping blocks 46a and 46b which clamp a right angle extension 21a of the exhaust fixture. With this arrangement, loosening of the clamping block permits adjustment of the clamping fixture in order to align passageway 2411 with the path of movement of mask supports when the exhaust fixture is in its illustrated exhaust position.

A water line 50 from a supply (not shown) extends along fixture 42 being supported thereby, and enters an intake 23d in the extension 24 of nozzle 23. Water admitted through this line permits purging of the fixture but that should be accomplished only when the exhaust fixture has been removed from its exhaust position. To that end, there is a further cam 32a rotatable with cam 32 to actuate a switch operator 51 which controls a valve 52 in water line 50. Preferably, the. arrangement is such that the valve when actuated admits water through the line to the exhaust fixture for a preselected purging interval. The details of this timing are of no particular moment.

In considering the operation of the described arrangement,it will be assumed initially that cam 32 has been displaced from the position shown in FIGUREI presenting a portion of maximum radial dimension to cam follower 37. This will have occasioned maximum rotation of shaft 35 in a clockwise direction and will have, by rotation of'this shaft, caused cam follower 43 to have traveled vertically upwardly of cam 43. In coursing cam 44, cam follower 43 will have caused fixture 42 to have been displaced in a counterclockwise direction to displace exhaust fixture 21 completely out of the plane of cap 10 and its flange. With the exhaust fixture in this, which is its rest position, the screening machine may cause a screening cart 14 to move into this station and present a cap section in this position illustrated in FIGURE 1. At this time, the programming system of the screening machine energizes drive 12 and rotates cap 10 at a selected speed. Directly thereafter and also under the control of the programming system of the screening machine, motor 30 is energized and rotates cam 32 to the position shown in FIGURE 1. As thisrotation takes place, the contour of the cam permits return spring 38 to displace shaft 35 in a counterclockwise direction and cause cam follower 43 to travel down stationary cam .44. As cam 43 reaches the flat portion of stationary cam 44, spring 45 is permitted to rotate lever 42 in a clockwise direction so that the conjoint effect of the counterclockwise direction of shaft 35 and the clockwise direction of lever 42 places nozzle 23 in the exhaust position illustrated in FIGURE 2. Preferably, the contouring of cam 32 is such that guide portion 24b of the nozzle engages flange b of the tube cap before switch operation 33b operates one of the limit switches to de-energize motor 30 and arrest cam 32 in the position shown in FIGURE 1. This gives freedom of movement for the exhaust fixture which, while not particularly necessary to the processing of a round cap, is highly desirable in the processing of rectangular tube caps. With the exhaust nozzle in position and the cap rotating in a clockwise direction about the axis of workholder 11, mask supports 10c travel through the passageway 24a of the nozzle 23. During this travel, the exhaust or suction created in channel 22 by system 20 creates an air stream as indicated by the arrows in FIG- URE 3 from the extreme end of nozzle 23. This air current encircles any mask stud 100 that may instantaneously be within passageway 24a of the nozzle and draws off any water that may have been deposited on the support in the trim process of the preceding station of the screening machine.

The programming of the screening machine retains fixture 21 in its exhaust position for most of the period during which the tube cap 10 is rotated at the workstation under consideration and this is usually a minimum of several revolutions. As a consequence, the exhaust system will remove water from all of the mask studs of the cap in this station.

At the time the programming system of the screening machine is to step the screening cart from this station to the next succeeding one, motor 30 is first energized to drive the cam 32 in a clockwise direction and restore fixture 21 to its rest position. The relative orientation of cams 32 and 32a is adjusted to the end that switch operator 51 is actuated when nozzle 23 has been lifted clear of cap 10. At this time, valve 52 is actuated and water is admitted through line 50 to purge nozzle 23- and exhaust channel 22. The purging water is usually directed to a reclaim reservoir since the fluid taken from mask supports 10c in the operation of the exhaust system frequently contains phosphor that should be reclaimed. As motor drive 30 returns exhaust fixture 21 to its rest position, the purge will have been completed and the water supply shut off.

When cap 10 leaves the described work station with its mask supporting studs 10c freed of water or slurry deposit, the cap will have been prepared to receive its assigned mask. Since the studs have been cleaned and dried, the engagement of the mounting springs of the mask with studs 100 will not cause water to be splashed on the slurry coating of the cap and the disadvantage previously experienced from excess Water carried by the mask supports will have been obviated.

While a particular embodiment of the invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

I claim:

1. Apparatus for processing a color cathode-ray tube having a cap section comprised of an image screen area surrounded 'by a continuous flange having supports for mounting a color-selection mask in predetermined spaced relation to said screen area, said apparatus comprising;

a workholder for supporting said cap section for rotation;

an exhaust system including a fixture having an exhaust channel extending therethrough and terminating in a nozzle which has a recess dimensioned to at least partially enclose one of said mask supports of said cap section, said fixture being movable from a rest position in which said nozzle is out of the path of movement of said mask supports to an exhaust position in which at least one of said mask supports is presented to said recess of said nozzle;

and means for moving said exhaust fixture between said rest and exhaust positions in timed relation to the rotation of said cap section by said workholder.

2. Color tube processing apparatus;

in accordance with claim 1, in which said nozzle has a guide portion for engaging said flange to position said nozzle relative to said mask supports.

3. Color tube processing apparatus in accordance with the preceding claim in which said guide portion is shaped to engage said flange in a substantially line contact.

4. Color tube processing apparatus in accordance with any of the preceding claims in which said nozzle forms a continuation of said exhaust channel, in which said recess is in the form of a passageway extending across said exhaust channel, and in which said passageway at least partially encloses the path of movement of said mask supports when said fixture is in its exhaust position.

5. Color tube processing apparatus in accordance with any of the preceding claims have means for purging said exhaust fixture.

6. Color tube processing apparatus in accordance with the preceding claim including means for operating said purging means only after said exhaust fixture has been removed from said exhaust position.

No references cited.

ROBERT W. MICHELL, Primary Examiner. 

1. APPARATUS FOR PROCESSING A COLOR CATHODE-RAY TUBE HAVING A CAP SECTION COMPRISED OF AN IMAGE SCREEN AREA SURROUNDED BY A CONTINUOUS FLANGE HAVING SUPPORTS FOR MOUNTING A COLOR-TELEVISION MASK IN PREDETERMINED SPACED RELATION TO SAID SCREEN AREA, SAID APPARATUS COMPRISING: A WORKHOLDER FOR SUPPORTING SAID CAP SECTION FOR ROTATION; AN EXHAUST SYSTEM INCLUDING A FIXTURE HAVING AN EXHAUST CHANNEL EXTENDING THERETHROUGH AND TERMINATING IN A NOZZLE WHICH HAS A RECESS DIMENSIONED TO AT LEAST PARTIALLY ENCLOSE ONE OF SAID MASK SUPPORTS OF SAID CAP SECTION, SAID FIXTURE BEING MOVABLE FROM A RESET POSITION IN WHICH SAID NOZZLE IS OUT OF THE PATH OF MOVEMENT OF SAID MASK SUPPORTS TO AN EXHAUST POSITION IN WHICH AT LEAST ONE OF SAID MASK SUPPORTS IS PRESENTED TO SAID RECESS OF SAID NOZZLE; AND MEANS FOR MOVING SAID EXHAUST FIXTURE BETWEEN SAID RESET AND EXHAUST POSITIONS IN TIMED RELATION TO THE ROTATION OF SAID CAP SECTION BY SAID WORKHOLDER. 